The present invention generally relates to the installation of architectural lighting fixtures, and more particularly to the suspension of lighting fixtures below a grid ceiling system and to providing an optional electrical feed at a point of suspension.
Heretofore, lighting fixtures have been supported below grid ceilings using cumbersome support hardware that is relatively difficult and costly to install. Prior methods of support involve, for example, the use of separate support members such as angle irons or unistruts which are cut to a required length at the job site. These support members are positioned on top of or above the grid ceiling at specified fixture support locations, and then they are anchored to the building superstructure by overhead load wires. (In earthquake prone areas the load wires must, in addition to supporting a vertical load, provide lateral support.) Wherever an electrical feed is required, an electrical junction box must be installed along with the anchored support member. For this purpose, commercially available mounting rails that fasten to the T-bars of the grid ceiling system are commonly used. Mounting rails installed across individual squares of the ceiling""s T-bar grid structure permit the junction box to easily be located within selected grids. Sometimes a load wire is dropped directly to the mounting rail and attached by means of a wire clip, however, without independent support the load carrying capacity of such an arrangement is limited.
U.S. Pat. No. 5,484,076 to Stephen Petrushka discloses a load-bearing mounting bracket and bracket assembly used with conventional mounting rails that greatly simplifies the process of installing lighting fixtures below grid ceilings as compared to the conventional installation approaches above-described. In the Petrushka patent a saddle-shaped load-bearing mounting bracket straddles and is adjustable along the mounting rail and permits easy and secure attachment of overhead load wires to the point of suspension of the lighting fixture. The Petrushka mounting bracket can also optionally be used with an electrical junction box to permit its use at electrical feed locations as well as non-feed locations. Thus, the same mounting hardware can be used cost effectively in a variety of different installation environments to meet different installation requirements.
However, the Petrushka mounting bracket has a notable limitation: the only structure to which it can be mounted is an accessory mounting rail of the grid ceiling system. This means the bracket is limited to off-grid suspensions, that is, to suspension locations between the T-bar members of the ceiling""s T-grid; where a desired suspension point falls directly on a T-bar (an on-grid suspension point) different hanging hardware must be used. The need or potential need for additional hardware increases stocking requirements and the risk that needed hardware will not be readily available at the job site when the fixtures are hung, resulting in lost time and increased labor costs.
The present invention overcomes the limitations of the Petrushka mounting bracket by providing a hanger bracket, hanger bracket assembly and method for hanging a lighting fixture from off-grid or on-grid suspension locations using the same hanging hardware, thus eliminating the need for more than one type of hanging or mounting hardware for a particular job site. The invention provides a hanger bracket that is inexpensive to manufacture and that readily and adjustably attaches to either the ceiling""s T-bars or its accessory mounting rails.
The present invention also permits suspension of a lighting fixture below a grid ceiling at an electrical feed point, and addresses the labor inefficiencies of having to wire the fixture directly to an electrical junction box above the ceiling. Typically, once lighting fixtures have been hung from a grid ceiling structure, an electrical contractor must be called back to wire the fixtures at a relatively high labor charge, adding significantly to cost of the installation. Also, if the fixtures are moved, for example, to accommodate a reconfiguration of open office furniture systems, rewiring is normally required which again requires an electrician. An aesthetically pleasing installation also requires that the electrical feed be unobtrusive as possible. To accomplish this, the fixture power cord is run up to the ceiling as close to the fixture""s suspension cable as possible and fed through a ceiling canopy which covers the hanging hardware and holes cut in the ceiling tiles to accommodate the hanging hardware and wires.
The present invention provides a means for hanging or moving architectural lighting fixtures in an architectural space in a manner that permits electrical feeds to be simply plugged in at the ceiling in a manner that maintains the aesthetics of the installation. Electrical feeds can thus be provided by the installer of the fixture without the need of an electrician or electrical contractor, other than to provide the initial wiring to preselected electrical feed locations.
Briefly, the invention provides for a load-bearing hanger bracket for suspending a lighting fixture from on-grid and off-grid locations within a grid ceiling system. The hanger bracket is comprised of an elongated bracket body having a base end, a top end, and at least one load bearing wire attachment point. A first attachment structure is provided at the base end of the bracket body for attaching the hanger bracket to a T-bar member of a grid ceiling at a selected location along the T-bar, while a second attachment structure is provided for optionally mounting to an accessory mounting rail connected between opposed T-bars at a selected location along the mounting rail. By providing dual attachment structures, the hanger bracket can be used to hang lighting fixtures from a T-bar of a grid ceiling system or from a mounting rail between T-bar members depending on where in the grid ceiling system the fixtures are to be located.
In a further aspect of the invention, an electrical junction box is provided with the hanger bracket to provide a hanger bracket assembly having an electrical feed next to the fixture""s suspension point. In the preferred embodiment, a female plug is provided in the bottom wall of an electrical junction box so as to provide an electrical outlet at the ceiling. A ceiling canopy, which covers the hanger bracket and electrical outlet, is provided with an opening through which a male plug, provided at the end of a lighting fixture power cord, can be inserted. Using the hanger bracket assembly of the invention, a lighting fixture can easily be installed with an electrical feed and with a clean, architecturally pleasing interface at the ceiling surface.
In still another aspect of the invention, a method is provided for electrically connecting lighting fixtures suspended below a drop ceiling, such as a grid ceiling system. The method includes providing electrical outlets at preselected lighting fixture suspension locations above the drop ceiling wherein each of the electrical outlets has a female plug having a downwardly facing plug end extending to the drop ceiling next to a suspension location for the lighting fixtures. The method further includes wiring the electrical outlets so as to electrify same, and hanging lighting fixtures from the drop ceiling having power cords with a male plug end of sufficient length to reach the ceiling. After the fixtures are hung, their power cords are simply plugged into the female plugs of the pre-wired electrical outlets above the drop ceiling next to the suspension location of the fixtures. The ceiling can be provided with an array of prewired electrical outlets which can be used to install lighting fixtures at preset locations or to move lighting fixtures from one preset location to another.
Therefore, it can be seen that it is a primary object of the invention to facilitate the hanging of electric lighting fixtures below grid ceiling systems. It is a further object of the invention to reduce the hanging hardware necessary to hang lighting fixtures from various locations within the grid ceiling system. It is still another object of the invention to reduce labor costs for lighting fixture installations. It is yet a further object of the invention to facilitate the moving of lighting fixtures from one location to another beneath a drop ceiling, by eliminating the need for rewiring. Yet other objects of the invention will be apparent from the following specification in claims.